Water eliminator



Feb 21, 1937 w. M KENNA 3,304,696

WATER ELIMINATOR Filed Nov. 24, 1964 JIG) 2 INVENTOR.

FREDERIC W. MKENNA 525M C Q? ATTORNEY United States Patent M 3,304,696 WATER ELLNHNATOR Frederic W. McKenna, Webster Groves, Mo., assignor to American Air Filter Company, Inc, Louisville, Ky., a corporation of Delaware Filed Nov. 24, 1964, Ser. No. 413,543 3 Claims. (Cl. 55-268) This invention relates to apparatus for collecting water blown off a cooling coil by a high velocity horizontal air stream.

Ordinary air stream velocities do not pose serious problems of water carryover from a cooling coil serving to dehumidify the air stream. Condensate collected on the coil fin surfaces simply drains down the fin surfaces to a drain pan. However, when cooling coils are subjected to air velocities exceeding about 600 feet per minute, water removal problems of greater degree are encountered. While conventional water eliminators can be used to remove the water from the air stream, they present a relatively high resistance to air flow.

The object of the present invention is the provision of apparatus which provides adequate water removal from a high velocity horizontal air stream in a limited space downstream of a coil, but does not impose an unduly high resistance to air flow.

Apparatus according to the invention takes advantage of the trajectile path of water droplets which are blown off the downstream face of the high velocity coil by arranging a number of surfaces in locations to intersect the paths of the various droplets.

To accomplish this a series of generally horizontallyextending trays are arranged in generally tier formation a specified distance downstream from the downstream vertical face of the coil. The spaces in a vertical direction between the trays are determined so that each tray encompasses a horizontal area through which droplets blown off a specific portion of the coil will pass as a result of their particular trajectory corresponding to the particular air velocity. The trays are generally trough-shaped in section so that gravity will urge the droplets captured by the contact with the upper surface of the trays into the drain trough provided in each tray rather than being again carried off by the air stream. A further desirable provision of the apparatus according to the invention is the use of a material on the upper surface of the trays which permits the drainage but prevents reentrainment into the air stream.

The invention will be described in somewhat more detail in connection with the accompanying drawing illustrating apparatus embodying the invention by way of example, and wherein:

FIGURE 1 is a vertical section through a fragment of a duct containing a high velocity cooling coil and apparatus according to the invention; and

FIGURE 2 is a plan view of a fragmentary portion of the duct of FIGURE 1, with parts broken away.

In the drawing the horizontal air flow duct is defined by top wall 10, bottom ball 12, and opposite side walls 14 and 16. The air flow is generally horizontal as indicated by the arrows in each view, and is indicated in the drawing as passing successively from right to left through the cooling coil 18, the open space 22 immediately downstream of the downstream face 20 of the coil, and then through the water eliminator section generally designated 24-.

The eliminator section comprises a series of relatively flat trays or trough-shaped elements 26 which extend horizontally between the opposite vertical side walls 14 and 16 of the duct to provide a series of vertically-spaced, generally horizontally-extending surfaces lying in the tra- 3,304,696 Patented Feb. 21, 1967 jectile paths of water droplets blown ed the downstream face 20 of the coil. One preferred cross-sectional shape of the trays 26 is that shown in FIGURE 1 in which a shallow V is formed with a drain trough 28 provided at the point area of the V and extending for the length of the trays. In that view the front portion 30 and the rear portion 32 of the tray embrace an included angle of about degrees. The individual drain troughs 28 are each connected to a drain location 34 outside the duct and which may be a vertical pipe into which the individual drain troughs 28 are fed.

To reduce re-entrainment of the water collected on the top surfaces of the trays 26, the front and rear portions 30 and 32 have upper surfaces covered by a material 36 which essentially serves a wioking purpose. Water droplets carried against the upper surfaces of the trays by their trajectories strikes the material 36, with splashing greatly reduced, and then pass down through the material to the drain trough 28 without being again picked up oif thetrays by the air stream. In one form the wicking material 36 may be a relatively thin sheet (e.g., Ms inch thick) of open cell polyurethane foam material of, say, 20 cells per inch texture.

The arrangement of trays in the generally vertical tier formation shown'provides for the eflicient collection of water from the horizontally directed air stream at the relatively high velocities in the magnitude of 600 to 1000 f.p.m. at a relatively low air pressure drop. For example, with a coil face velocity of about 750 f.p.m. and a vertical spacing between five-inch wide trays of four inches, the pressure drop encountered is less than the 0.1 inch water gauge.

It will be apparent that a number of dimensional relationships exist in the described structure, and that varia tions in these dimensional relationships beyond a certain limit will usually result in :a variation in both the collection efiiciency and the pressure drop imposed by the eliminator section. An example of satisfactory relationships will be outlined in relation to FIGURE 1 in which the dimension between the rear face 20 of the coil and the upstream edge of the water eliminator section is indicated by the letter Y, the vertical spacing between trays is indicated by the letter X, and the vertical distance between the top wall 10 of the duct and the upstream edge of the upper tray is indicated by the letter A. With each tray having a depth or distance in the direction of air flow of about five inches, the following examples of dimensions which yield satisfactory results for particular air iiow velocities are provided in the table.

The locational dimensions set forth above are provided as a guide for a specific tr-ay width of five inches and are not intended to constitute limiting values as to the location of the trays Within the scope of this invention. Thus it will be apparent to one skilled in the art that a change in tray width from front to rear will require a corresponding change in other dimensional relationships to achieve the same collection efficiency, that the vertical spacing between the trays will likewise have a corresponding effect, and that a variation which will increase water collection efiiciency will likely increase the pressure drop imposed by the section.

An eliminator according to the invention is also very useful in a duct system where it is desirable to turn the air shortly after it exits from the downstream face of the coil. For example, even with the 1000 f.p.m. velocity, the Y distance plus five inch blade width totals only 8 /2 inches before the turn can begin.

I claim:

1. Apparatus for capturing condensate droplets blown off the downstream face of a cooling coil through which high velocity air moves generally horizontally, comprising:

a tier of vertically-spaced, relatively shallow horizontal trays extending for substantially the height of the downstream face of sail coil, said trays being spaced apart a selected distance to provide substantially open spaces therebetween to form unobstructed generally horizontally directed linear air flow paths between successive trays, each of said trays extending substantially horizontally to present an upper face encompassing an area through which said droplets blown off a given height of the downstream face would be carried at the selected velocity of air passing through said coil, with successively higher and successively lower trays being spaced accordingly so as to encompass the areas through which droplets blown from successively higher portions and successively lower portions of the downstream face of said coil would be carried when following a normal gravity induced trajectory; trough means cooperatively disposed in the lower portion of said shallow horizontal trays to receive condensate from said shallow trays and to conduct such condensate from said shallow trays; and, moisture permeable materials covering the upper surfaces of said shallow trays to receive condensate droplets carried into contact with said upper surfaces and to conduct such condensate to said trough means for removal from said trays.

2. The apparatus of claim 1 in which:

said trays of a shallow V shape in cross section are upwardly open and include trough means at the point area for carrying the collected condensate out of the air stream wherein said trough means is disposed generally transverse to the direction of flow of said air stream and wherein one side of said V- shaped tray extends downstream from said trough means, and the second side of said tray means extends upstream from said trough means so said trough means forms the low point of said V-shaped tray and the upper surface of said first side and the upper surface of said second side are covered with moisture permeable material to receive condensate droplets carried to said shallow trays to conduct such condensate to said trough means for removal from said tray. 2

3. The apparatus of claim 3 in which:

said moisture permeable material is open cell polyurethane foam.

References Cited by the Examiner UNITED STATES PATENTS 813,217 2/1906 Kinealy --257 1,845,750 2/1932 Hillery 261-116 1,917,043 7/1933 Lewis 62-290 X 1,975,066 9/1934 Sanderson 62-93 2,997,131 8/1961 Fisher 55-466 3,190,057 6/1965 Sinex 55313 FOREIGN PATENTS 134,873 11/1919 Great Britain.

HARRY B. THORNTON, Primary Examiner.

ROBERT F. BURNETT, Examiner.

D. TALBERT, Assistant Examiner 

1. APPARATUS FOR CAPTURING CONDENSATE DROPLETS BLOWN OFF THE DOWNSTREAM FACE OF A COOLING COIL THROUGH WHICH HIGH VELOCITY AIR MOVES GENERALLY HORIZONTALLY, COMPRISING: A TIER OF VERTICALLY-SPACED, RELATIVELY SHALLOW HORIZONTAL TRAYS EXTENDING FOR SUBSTANTIALLY THE HEIGHT OF THE DOWNSTREAM FACE OF SAIL COIL, SAID TRAYS BEING SPACED APART A SELECTED DISTANCE TO PROVIDE SUBSTANTIALLY OPEN SPACES THEREBETWEEN TO FORM UNOBSTRUCTED GENERALLY HORIZONTALLY DIRECTED LINEAR AIR FLOW PATHS BETWEEN SUCCESSIVE TRAYS, EACH OF SAID TRAYS EXTENDING SUBSTANTIALLY HORIZONTALLY TO PRESENT AN UPPER FACE ENCOMPASSING AN AREA THROUGH WHICH SAID DROPLETS BLOWN OFF A GIVEN HEIGHT OF THE DOWNSTREAM FACE WOULD BE CARRIED AT THE SELECTED VELOCITY OF AIR PASSING THROUGH SAID COIL, WITH SUCCESSIVELY HIGHER AND SUCCESSIVELY LOWER TRAYS BEING SPACED ACCORDINGLY SO AS TO ENCOMPASS THE AREAS THROUGH WHICH DROPLETS BLOWN FROM SUCCESSIVELY HIGHER PORTIONS AND SUCCESSIVELY LOWER PORTIONS OF THE DOWNSTREAM FACE OF SAID COIL WOULD BE CARRIED WHEN FOLLOWING A NORMAL GRAVITY INDUCED TRAJECTORY; TROUGH MEANS COOPERATIVELY DISPOSED IN THE LOWER PORTION OF SAID SHALLOW HORIZONTAL TRAYS TO RECEIVE CONDENSATE FROM SAID SHALLOW TRAYS AND TO CONDUCT SUCH CONDENSATE FROM SAID SHALLOW TRAYS; AND, MOISTURE PERMEABLE MATERIALS COVERING THE UPPER SURFACES OF SAID SHALLOW TRAYS TO RECEIVE CONDENSATE DROPLETS CARRIED INTO CONTACT WITH SAID UPPER SURFACES AND TO CONDUCT SUCH CONDENSATE TO SAID TROUGH MEANS FOR REMOVAL FROM SAID TRAYS. 